Hi Bill,

Thanks for your response. Yes, I am running the MAPDL codes directly. I want to obtain a stiffness matrix with all the dofs in the original base sector included.

Let me explain clearly how I attemped to do that.

% The reference sector model in Ansys firstly undergoes a cyclic static 
% analysis in order to include the rotation-induced prestress effect.

% Then a linear perturbation modal analysis for the sector model with
% cyclic symmetry and without any constrained dof is performed in order to
% export the sector-level mass/stiffness matrix (of only the original base sector) for % the following model reduction research. 

After the second step, Ansys gives the exported matrices of the original base sector. However, a part of the DOFs attached onto the cyclic symmetry interfaces are condensed in the exported K and M matrix. More specifically, both the high and low cyclic interface dofs are partially retained in the global matrix. 

Now I'm trying to write some codes in order to read the imcomplete sector matrix and further to restore the terms related to the condensed cyclic interface dofs.

But this is not a easy task. Hope I can make it.